Nowadays, with the development of communication technology, there emerge more and more input systems applied to various communication terminals (such as mobile communication terminals, personal digital assistants (PDA), smart phones, desktop computers, notebook computers, and tablet PCs, which are based on communication protocols for various communication systems). However, current input systems share the following disadvantages: 1. they are insensitive to the identity of the communication counterpart in a text chat and insensitive to the social relationship between the user and the communication counterpart; 2. due to the insensitivity to the social relationship, it is difficult for the input systems to properly choose among everyday casual language, self-effacing language, and respect language for respective words.
For example, in a Chinese input method, for a female user, when referring to “you”, she needs to use different words for different persons. When the counterpart is the female's husband, she usually uses the Chinese word for “husband”; when the counterpart is a business partner, usually the Chinese word for “your honor” or “our dear customer” shall be used; when the counterpart is the female's father, she usually uses the Chinese word for “your honor” or “Dad”. Furthermore, in Chinese, to show respect to the counterpart, one usually uses respect language and self-effacing language, which is directly reflected in the phrasing and grammar. For example, when expressing “I'm sorry”, the user of an input method generally will dynamically select his wording based on the social relationship between himself and the counterpart. As an example, when the counterpart is a subordinate or is younger, one usually says “sorry”, indicating a relatively light degree of apology; when the counterpart is one's colleague, he usually uses “I am sorry”, indicating a normal degree of apology; when the counterpart is one's elder, teacher, or commercial customer, he usually uses the very formal expression “I am very sorry”, indicating a more sincere and higher degree of apology. In this way, when the communication counterpart is a user's elder, teacher, or business customer, in the case the user inputs the text “sorry”, it will better serve the purpose of the communication and correct the user's improper wording if the input method displays a prompt to the user saying that it is better to use “I am very sorry” or an even more respectable term. Accordingly, it is necessary to have an input method that can provide candidate words suitable for the social relationship between the user and the communication counterpart.